Charge forming device



Feb. 14, 1933.. F E. ASE-LUNE 1,897,103

CHARGE FORMI NG DEVICE Filed July 3, .1929

Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE.

FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION,

OF DAYTON, OHIO, A CORPORATION OF DELAVJ'ARE CHARGE. FORMING DEVICE Application filed July 3,

This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this character which comprise plurality of primary carburetors which deliver a primary mixture of fuel and air to aplurality of secondary mixing` chambers i rated adjacent the engine intake ports, and in which the primary mixture is iniLed with additional air under certain operating conditions.

A device of this character is disclosed in the copending application of Fred E. Aselivilford H. rleeter and Carl H. Kindl, No. 288,683, tiled June 10, 1928, to reference may be had for a` full dissure of the device shown. herein.

one object ef the present invention to improve the operation of devices of this chnracter during the acceleration period and particularly to provide means for enriching the mixture during the acceleration period having means associated therewith to prevent too great enrichir ent of the mixture during acceleration at relatively high engine speeds.

lt is another object of this invention to prevent ratcheting of the air valve, that is a tendency for said valve to move toward closed positions as a result of the effect of engine pulsations when the engine is operating at low speed under heavy load with a relativehvv wide open throttle.

In certain earlier devices of this character means have been provided for enriching the mixture on opening movements of the throttle which include means for retarding the opening of the air valve under such operating conditions. lt has been found in certain of these devices that the valve is retarded to so `great an extent that when the throttle is opened relatively high engine speed, the mixture enrichment is sufficient to cause loadi or" the engine. 1t has been found in devices of this character when a dash pot is employed to resist the opening movement of the air, the valve will gradually move toward closed position if the engine is operating very slowly under heavy load with rela- `tively wide open throttle. This action is apparently due to engine pulsations, the ef- 1929. Serial No. 375,688.

feet of which is not noticeable during operation under other conditions. Jaccording to the present invention means are provided forv partially relieving the resistance of the air valve dashpot when the throttle is opened at high speed, said means being automatically rendered effective by the auxiliary air valve during its opening movement accompanying the throttle movement and effective to eliminate too much enrichment of the mixture on opening of throttle as well as the tendency for the air valve to close in the manner above described.

Further objects and advantages of the present invention will be apparent from the follewin description, referencebeing had to the accompany-,fing drawing wherein a pr ferred embodiment of one form of the present invention is clearly shown.

ln the drawing;

Fig. l is a vertical, longitudinal section through a charge forming device constructed in accordance with the present invention and the intake port with which it is associated.

Figs. 2 and 3 are transverse, vertical sections on the lines 2 2 and 3 3 respectively.

Fig. i is a left-hand side elevation of the device, certain parts being shown in section.

Fig'. 5 is a detail view of the throttle operating mechanism.

The device disclosed comprises a main air manifold 10, having three outlet branches, the middle branch 12 being shown herein. Each of these branches communicates with one of the intake ports 14- of a multicylinder engine. The outlet branches are cach provided with an attaching liange 16 for securing the manifold to the engine bloclr in the usual manner, and a flange 18 to which the carburetor unit is secured.

The carburetor unit comprises a main housing` 20, having an attaching flange 22, adapted to be secured to the flange 18 by screws Q4. An air inlet coupling Q8 is secured in position to register with an opening in the upper wall of the hcusingQO, in any suitable way and may be connected with an air cleaner if desired. A casting 30, in which the passages supplying fuel to the nozzles are formed, is secured by screws to the lower Wall l i y 1,897,103

of housing 20, and a sheet metal fuel bowl 32,

Y is held tight against an annular shoulder 34 Von the housing by any suitable means.

Fuel is conducted from a main source of supply to the fuel bowl through a conduit (not shown) `and the flowl of fuel to thebowl is controlled by a float 36, operating in the usual manner to maintain'a substantially constant level of fuel therein.

Fuelliows fromthebowl 32-to al plurality of .primary fuel nozzles 38, one of which is located in each of the primary mixing chambers 40,the construction of which is briefly described hereinafter. The fuel 'conduit between the fuel bowl and the nozzles comprises thevertical fuel passage 42 communicating at its upper endY with the' horizontal fuelvcanal 44, which connects with each lofthe nozzles 38 through an or-iliee46. Fuel is admitted fromk the fuel bowl to the passage 42 at all engine j speeds, through a fixed metering `orifice 48 audat high speeds additional fuel isa'dmitted through an orice 50 controlled by avalve v52operated'in the manner set forth in the 25' above mentioned application. This operatingmeans forms no part of thefp'res'ent inl vention and need not be described,furtherk herein. .Y Fuel is'lifted fromthefuel bowl through the abovedescribedfuel passages and noz zles 38ito the primary'mixing chambers by the suction therein. Opening movements of the throttle5 causey aV-reduction in mixing chambersuction which might permit the fuel column-to drop sufficiently to causea temporary' fuel starving of the engine unless means are provided to prevent this action." For this.

purpose a check valve 54 isprovided in an en- 'larged chamber 56 at the junction `of the channels 42 and 44, and on 'reductionV of mixing chamber suction, seats onthevbottom of the chamber, preventing downwardY lflowjof Each primary fuel nozzle is provided with a main fuel'outlet 58 in the top of. the" nozzle and a secondary fuel outlet Vcomprising two oriicesG() and 62 in the vertical wall'of the#V nozzle near` the bottom oftne mixing chamber. AtV relatively high speeds, the mixing chamber Vsuction is sufficient to lift` fuel from the main outlet Vas well as from oric'es l60 and 62. d At idling, orlow speed operation underload, however, the suction isenough to lift fuel only toV some point between the vtop ofthe nozzleand the 'orifices 60 and. 62, fuel flowing from these orifices by the action of gravity underl such operating conditions.'

" Each nczzleis provided with a restricted'fuel Ametering orifice. 63. The. primary mixing chamberscomprise the enlarged anterior ends of the-primary mixture passages `64, which arejparallel to eachother and close together,

as indicated in Fig. 2,. 'Whenthe'carburetor is attached to the manifold, these passages register'with'conduits `which convey'the prij mary mixture to the secondary mixing cham bers, as fully disclosed in theapplication above referred to. 'Restrictionsrseparate the primary mixing. chambers from vthel Iemainder of the mixture passages to reduce the velocity of flow past the fuel nozzles for a purpose fully set forthin'thegabove men tioned copending application.

A single throttle valve 68, which extends` across allfthe Vprimary mixture passages, con;L

trols the lowtherethrough and isprovided with grooves 70, which register with saidrmix.- ture passages. This throttle is'operatedV in a manneri hereinafter Amore fully described.v Y

T'The Vmiddlev primary mixture passage com municates with a tube 7 2 fixed inthe manifold on astationary g l ide sleeve 84, fixed: in the y --housing 20,.'andserving also r'as a guide 4for the stem 86 towhich theair kvalve is secured.

Ybranch 12. VThisltube constitutes one of the Y v primary ymixture conduits above referred to.. Y and conveys theprimary mixture tothe sec` Y ondarymixing chamber locatedin the middle` l e5 i Vvhen it is desired to choke ,thecarburetor to J facilitate starting of 'the engine, the flange 80 is adapted to belifted by means not shown hereimbut fully vdescribed in the above application, until thejupperrend yof thesleeve 82 f engages ,the 'air' valve -to "hold :it closed;J

Suiiicient air to carry thestartingzfuel from the nozzles vto the intakefportsiisadmitted ,through an elongated slot" 87', vformed in a plate 88,.secured to the vhousing20, as shown j The valve 74 'admits sa 0 the if @imiter` 90, from which air flows totheV rimary mixf ture` passages through anwori cef9f2`in the bottom of the air chamber'a-ndto the sec-v ondary mixing chambers through a-passage` 94, which connects with the inlet of the mani-VV Y fold 10. vThe flow of air throughthis passage is controlled 'by a manually operable throttle `96, secured to a shaft 9 8, rotatably mounted in themain housing and byv a suction Operated valve 100,y secured'zto 'a shaft` 102, also-rotatably mounted in the mainfhousing. The operating connections forfthethrottle valves comprise an farm-'99i`lixed toa spindle 'V101 projecting from the primary throttle and provided: with'an 'orifice' 103 inwhich some suitable operating connection is adapted to be attached. This operating arm is connectedy Y by alost motionconnectionto .an arm rse- :cured byasuita'ble split clampr Atothe end ofvshaft98, lwhich projects outside the housing. An operating link? I10'( :is pivotally connected-to thearm 98 and a pin109l projecting from the free end of'armlOrproj-ects through a slot 111 in the link 107. A regulating screw 113 is threaded in lugs 115 project-ing from the inl 107 and may be adjusted to regulate the length of slot 111. A tension spring 117 is connected at one end to the upper end of the linlr 107 and at its other end to pin 109, the spring tending to hold the pin against the upper end of the slot.

lilith both throttles closed, the parts are in the position shown in Fig. 1 With the pin 109 in engagement With the screw 113. As the arm 99 is rotated in a countercloclrivise direction to open the primary throttle valve, the linl 107 moves downwardly to a position Where the upper end of slot 111 engages pin 109 before the operating arm 105 of the air throttle is moved, to permit a partial opening of the primary throttle independently of the air throttle. The degree of this opening may be adjusted by suitably adjusting the screvv 113, but the parts are generally so adjusted that the primary throttle is opened Without accompanying movement of the air throttle until the engine is running at a speed approximating a vehicular speed of twenty-twentyiive ailes per hour on a level.

0n opening of one or both of the throttle valves, the suction in the air chamber is increased and the valve 7 4 is opened to admit additional air and increase the quantity of mixture supplied to the engine. The opening of tl. *e is retarded to prevent fluttering of the valve and torestrict the admission of ai `o as to enrich the mixture to some extent Whenever the throttlcs are opened. For this purpose a dashpot is provided comprising a cylinder 104 Which receives fuel from the reservoir 32, and a piston 106, secured to the loiver end of the valve stem 86 by any suitable means. A. check valve 107 is provided in the bottom of the dash pot cylinder to admit fuel thereto on closing movements of the valve and to prevent escape of fuel therefrom as the valve is opened. construction of this dashpot is not material so far as this invent-ion is concerned, and may be any conventional form of liquid dash pot which will properly retard the opening of the air valve.

is hereinbefore stated, the valve 100 which 'for convenience may be termed an auxiliary air valve opened primarily by engine suction, after the valve 9G begins to open. Its opening movements are controlled by a dash- .d to this end an arm 108, having a foiaed end shoivn in Fig. 4, is secured on one end of the shaft 102 iu any desirable Way.

the forked end of this arm is a i proj e Jting from an arm 112 forming part of a bell-crank lever, Which is pivoted on the housing at 114, and is provided with another arm 116 pivotally connected at its free end to the upper end of a rod 118, in any desirable manner. The rod 118 has mounted on its lower end a piston 120, which rlhe specific y is slidable Within the cylinder 122. The specific manner of mounting the piston on the rod 118 is not material so far as the present invention is concerned, but is fully described in the above mentioned application. 14s the valve 100 is opened by engine suction, its movement is resisted by the dashpot, Which comprises the piston 120 and cylinder 122, and the resistance of this dashpot to the motion of said valve may be regulated by means of a manually adjustable valve 124, provided with a knurled head 126, by Which it may be turned. Adjustment of this valve Will regulate the area. of the fuel passage 128, which permits escape of fuel from the cylinder 122.

While the valve is primarily operated by engine suction, the movement of the valve 98 also tends to move said valve 100. For this purpose an arm 130 issecured in any desirable manner to the end of shaft 96and a pin 132, pivoted in the end of the arm has a hole therein in Which is received a rod 134, Which is pivotally connected at its lovver end to the arm 11G of the abof-.f'e mentioned bellcrank lever. Adjustably secured to the rod 134 at points above and below pin 132,are collars 136 and 138 respectively, and between these collars and movable collars 140 and 142 are helical springs 144 and 146, which normally hold the collars 140 and 142 in engagement with the pin 132. Obviously, any movement of the arm 130 Will compress one or the other of springs 144 and 146 and will tend to move the bell-crank lever, thus tending to move the valve 100 toward either open or closed position, as fully described in the above mentioned copending application.

1n addition to the enrichment of the miX- ture secured by restricting the flow of air past the main air valve, the air valve dashpot may also be constructed to operate as a fuel pump. For this purpose a pump delivery conduit 150 may communicate with the bottom of the dashpot cylinder and eX- tend to a horizontal passage 152 formed in a distributor block 154, secured to the lower face of the main housing. The channel 152 communicates with three vertical channels 150, which in turn communicate with channels 158 in the Wall of the main housing. Passages 160 admit air to the channel 152 to form an emulsion of fuel and air therein which is drawn into the primary mixture passage through the passages 158, in the manner fully described in the above mentioned application. This pump may or may not be employed with the present invention.

ln order to restrict the admission of air sufhciently during opening of the throttle at low speed to create suicient suction at the jets to provide a mixture of the desired richness, it has been found necessary to provide adashpot Which will so retard the opening of the valve 74 that the suction produced at i the jetsfduring opening movements: of .the

throttle-at high speed is toogreatand` rer sults in'the formation `of too rich 'a mixture.l under these conditions to Vproperly operateK -F the engine;V In' order to overcome this 'diflis cultyf; means Vare provided according 4to this invention to vaiy the resistanceivhicli the'L dashpot oii'ers tothe openingfofthe valve'.

When thethrottle is 'opened from different .positicnsl"Specifically, theresistance of ythel I daslipot is-:rediiced underthe operating con: ditionsdesci'ibed V.andjthis vis effected autov.'inatically by thefjd'ashp'ot 'controllingthe," f f movement of the valvelOO. g It Will be noted 15J; onexamination of Fig. 2 ,that theycylinders 10i and 122 are close together and separatedA by a Wall k162; A passage lllis formed in f this'wall and communicates .with the bottoml offthecylinder 104 as indicatedzby thenu-r ineral 163, Va.iclvvith thecylinder 122 about tivo-thirds. of the distance ,fromv :the bottom V "otfsaichcylinder .or atwhateveiipoint gives the desired, result as indicatedby the numeral 165. ,Under normal conditions,`.the upper Y end of `the passage llrclosed bythe piston; 120,?and said piston remains vin.A positionto" close this passage during fall open-ing move-I ments' of the throttle ,-untilthe throttleisj n`ioved' to;aV relatively ivideaopen: position, WhenftliepistonlQO Whichis opera-tedby the valvelOO passesfbelovv the upper endjoti the passage164 and permits a loivfof fuel froml fthespace belojvvthepiston 106 so .that the resistancetomovement of this 'piston isl much 1 reduced s after theV upper end of the passage 16a-is funcovered as 'described;` ."llt,` will` be pelear, therefore, that'vvhen the throttlefvis opened 1to1 increase the speed -vvhen the motor Tis alreadyfrunning at relatively-high speed i endless enrichment of the mixturelisrneeded,' the'resistance to opening'of the lair valveY is much reduced, resultingY in the admission oil Y more air for a corresponding vmovement of' the throttle and anincrease in quantitysot mixture supplied the engineV without afcorrespondingincrease in the proportion vofv the..

fuel therein; ,p D v. '.VAs :indicated hereinbefore,l itrlhas been rfound in earlier devices of this character that when Vthe engine is running slowly under `heavy load With relatively open throttle,

the vair valve is graduallyfinoved "toward closed ,positionA bythe eilect or engine pulsa-.l

tions.V Thisis due to the fact that such vpulsations reciprocate the valve to a certain cxtent and duetoVI the resistance ot the' Vdashpot to opening movement WhiletlieI closing move'- ment is comparatively tree, theclosing-movement during such Vreciprocations is 'greater than thefopening with the result, thatthe valveE is 'gradually moved toward 'itsseat7 so that Athe i mixture slowly becomes tooi-i'ch.I

By providing the by-pass constructed*accord-V ring to this invention to partially eliminateV the l ;Qi'resistance of the `dash pot when the throttle valve.v f

A charge forming device'for internalV opened? relatively iwide, Ithis objectionable act-ion oftheair valve Ais prevented. The byi pass'i164 therefore etfectstvvo very desirable i 1; JA'fcliarge `forming device for internal combustion `.engines Acomprisingv a mixing throttle controlling the flowlo'f mixturethere- 1 from, amain air valve controlling the Iadinis- V sion. of air thereto, means-controlling theop- Aeration of said v'alve,f'an` air 'passagegandpresn Y sureoperatedmeans in said passage,for regu- Y f 'chamber,{ fuel land air inlets 'therefon a y lating the) effect of" said VvalveV vcontrollingV j mea iis.l i .Y Y, 2." Atharge forming device or internal.'

com'b-ustion` engines -comprising y a mixing chambery-'html -and" 'air inletstherefor,

from, amain air valve controlling, the admis-vV sionof 'lair`thereto, means for resisting the opening movementiorsaid valve, an air pas- Y 'sage,and 'pressureY operated means in said passager; torlregulating the' resistance oifered' by said 'resistin combustionengines comprising aV mixing 'i chamber,V fuel andkair Qinlets thereforp a throttlecontrollingthe loWLo mixture there#4 tronna main airvalve controlling the admis-v U meaiisxto the movement of" mi i i. 3'. Af charge forming device for internal vthrottle controlling the lovv of mixture there-I V' I sionfoffairthereto, ajdash pot orresisting` Y openingV movement ofi the valve, an airpassagepand. pressure operated meansv in saidy passage/for regulating the resistance oiered v4; Afl hargezforming device for yinternal combustion engines' comprising a mixing chambeigfuel-fandair 'inlets' therefor, va throttle'controlling the flow of mixture there#` iroinfamain air valve controlling the admislsion of airtlieretofan auxiliary air valve, and

means controlled said auxiliary air valve for regulating .the operation'of said `main air combustion engines v comprising a Vmixing chanibeig fuel and pair' inlets therefor, a throttle controlling the flow of mixture therefrom, a lmain air.v valve. c ontrollingthe admis. sion. ofA air-thereto, an auxiliary lair" valve,

means controlling the operation of said main airvalve, and means controlled bysaid.v auxil iary air valve for regulating the 'operationofv said `controlling'I neafns.V k Y 6. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the flow of mixture therefrom, a main air valve controlling the admission of air thereto, an auxiliary air valve, means resisting the opening moveinentof the main air valve, and means controlled by said auxiliary air valve for regulating the resistance of said resisting means.

7. il. charge forming device for internal combustion engines comprising a. mixing chamber, fuel and air inlets therefor, a throttle controlling the flow of mixture therefrom, a main air valve controlling the admission of air thereto, an auxiliary air valve, means normally retarding the opening movement of the main air valve and means controlled by said auxiliary air valve for rendering said retarding means ineffective on opening of the throttle under certain operating conditions.

8. i charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the flow of mixture therefrom, a main air valve controlling the admission of air thereto, an auxiliary air valve, means normally retarding the opening movement of the main air valve and means controlled by said auxiliary air valve for rendering said retarding means ineffective after a predetermined opening movement of the t irottle.

9. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the flow of mixture therefrom, a main air valve controllinol the admission of air thereto, means controlling the operation of said valve, and means operated by the blast of t ie entering air for regulating` the effect of said valve controlling means.

l0. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a 'throttle controlling` the flow of mixture therefrom, a main air valve controlling the admission of air thereto, means controlling the operation of said valve` aauxiliary air pasl and means located in said auxiliary air sage and operated by the blast of air passin o' through said auxiliary passage for regulating the effect of said valve controlling means,

ll. il charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle cont 'olling the flow of mixture therefrom, a main air valve controlling the admission air thereto, a dash pot for retarding the opening movement of said valve, an auxiliary air passage, and means located in said auxiliary air passage and operated by the blast of air passing through said auxiliary air passage for reducing the resistance of the dash pot to movement of said valve.

l2. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlli the flow of mixture therefrom, a main valve controllii-ig the admission of air thereto, a dash pot for retarding the opening movement of said valve, an auxiliary air passage, and means located in said auxiiary air passage and operated by the blast of air passing through said auxiliary air passage When the throttle is opened to a predetermined position for reducing the resistance of the dash pot to movement of said valve.

13, frcharge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the flouT of mixture therefrom, a main air valve controlling the admission of air thereto, means for retarding the opening of the air valve vvhereby the mixture is enriched for acceleration and the said valve tends to move toward closed position because of ...ie action of engine pulsations during operation under certain predetermined conditions, and means for modifying the action of the retarding means when the engine is operating under said conditions, whereby the effect of engine pulsations is eliminated and the mixture is prevented from becoming too rich at high engine speeds.

14. A. charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the floiv of mixture therefrom, a main air valve controlling the admission of air thereto, a dash pot for retarding the opening of the air valve whereby the mixture is enriched for acceleration and the said valve tends to move toward closed position because of the action of engine pulsations during operation under certain predetermined conditions, and means for reducing the resistance of the dash pot when the engine is operating under said conditions whereby the effect of engine pulsations is eliminated and the mixture is prevented from becoming too rich at high engine speeds.

l5. A charge formino' device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controlling the flow of mixture therefrom, a main air valve, an auxiliary air valve, dash nots controlling the motion of both said air valves, and a passage connecting the cylinders of said dash pots and permitting a flow of liquid from one cylinder to the other under certain operating conditions.

16. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a throttle controllingl the flow of mixture therefrom, a main air valve, an auxiliary air valve, dash llO i pots controllingI 'the Vmotion of Abothsaid air ,Vvalves,rand a passage'permitting-escape of Y io fueLfromthe dash pot controllingthe main` auxiliary valve. j 17 A; charge v a `main airyalve, an auxiliaryairvalvm*dash pots controlling the motion of both said air.

valves, and a' passage permitting escapefof fiiel from-the main airvalve dash pot, said passage being normally closed by; the-,piston of the dash pot governing the auxiliary 'valves'and adapted to be opened'aftera predetermined movement ofsaid auxiliary* t tliefuel reservoir 'and adapted to'control the valve. i p y Y y 18. Aichargeforining device forfinternal combustion engines comprising ay plurality of secondary mixing chambers, ai plurality of primary carburetors adapted 'to supply a primary mixture thereto7 means for supplying fuel and' air Vto saidcarburetors, a main air valve controlling admission of air toall 'of said carburetors, an anxiliaryair valve regulating the flow ofairto Vall of saidlsecondary mixing chambers, meansV controlling the operation of said main 'aiif-valve and' Y meansjoperated 'by said *auxiliary*t airvalve apassage admitting air to'said mixingchain;` ber, asuetion operatedvalve in said passage',

19.5 A rcharge .forming device for' internal Acombustion engines Comprising a fuelreser-V` Voir, ainixingzchamber, a4 fuel inlet therefor,

ia dash potfor controllingtheopening move-V ment of said valve comprisinfT a cylinder and 1 piston: slidable therein and an additional sucf said auxiliary cylinder normally Theld in I t forming .device for internal lcombustion engines comprising mixing:- 4chamber;'fuel and 'air inlets theref0i",aV throti tle controlling the flowof' mixtureltherefroim I22. 1A; t ycombustiony engines comprising a V'fuel' reserngcl'iani- I ber, a suction operated valvelin. said' p'assage,y ada'sli pot for controlling the opening movef ment-of said valve `comprising a cylinder and' piston slidable therein,V an` auxiliary cylinderl sition to-'ienderthe dash pot?effective, adapted to be moved to apositiongto render the daslif-pot' ineffective when thereis any `Charge forming device'for internal Voir, a mixing chamber, afuel inlet therefor,

to' ut relatively great-increase in suction on the air t potvfor resisting opening movementsof said valve comprising a cylinder and a piston v piston fin *said auxiliaryoylinder, a port in said auxiliary Cylinder `Communicating with.

resisting effect of the-dash pot',v and means normallyvholfling the last-named piston in positionzto close' the port 23. A cha ge formingjdevioe for internal combustion engines comprising a fuel reserl a suction"v operated valveheontrolling kadmisvalve-compiising a cylinder vand a piston slidable thereim an auxiliary ,cylindery coni- Iniiinicatingwith the dashgpot cylinder, a piston in saidlauxiliar'ycylinderga (port lnsaid 1 Y w slidable tiiereinfan auxiliary vcylinder -coni- 80 .miinicating' with: the: dash'pot cylinder, a

'sion air to saidv mixing chamber7 a dash *pot for resisting openingnioveinents ofl said auxiliaryxcylinder communicating vwith the Y.

fuel vreservoir 'and adapted to control the Vresisting effectV ofV the dash pot,'resilientmeans normally holding the piston in saidV auxil- Viary` cylinder in position to close the port and render the'dash pot effec-tive to resist normal opening movements of the' airvalve, said resilient means being adapted-to yield to permit movement off the last. named' piston to positionto openthe port? andV render the dash potineffectivewhen the suctionon the air ,valveL is 'siiiiicient to overcome the pressure .ofsaidresilient means on the piston.y v l e In testimony whereofv I-hereto Vaflix my'V signature.

FRED un'. zAsniiTiNn.

v i Vcommunicating With the dash l:pot cylinder, a 11 l port in said auxiliary cylinder communicating with said fuel reservoir 'andi adapted to 21. A charge {forni/ing device .forrinter'nal combustion enginescomprising al fuel reservoiiga ,mixinglchamben fuel inlettherefor, a suction operated'valve controlling admis# "sion of air to said mixing chamber; a dashf vot for resistino` o enin movementszofsaid valve comprising a cylinder and'apistonslid-l I l iable therein, an auxiliary cylinderlcommuniv iio "15," a suotionpioperated valve' controlling admis-Q sion ofgairgtosaidfinixing Chamber, a dash Y to render the ldash i I90 I Y fvoir, yafniixingfohamber;la -fuel 'inlet therefor, f 

